This section on energy is currently divided into three parts. In the first part are some general questions and ideas about energy use. In the second section are reports on projects produced by sophomore chemistry students at Punahou. In the third are links to other web resources with regard to energy.
I. Questions and Ideas
Identify everything that uses electricity in your classroom. Is every use efficient? Is waste occurring?
Air-conditioning takes up a lot of electricity, and there are many cases when it is left on with no one in the room
I agree, I really is not necessary to have the air conditioning on in the room without anyone in it. But what I don't get is why people have the air conditioning on and they leave the two doors open. What is the point? Is it too cold? My friends were telling me that some of the classrooms don't have control of the air-conditioning and some do. If not, what can we do to help control the problem? One of my friends told me that the air-conditioning works extra hard because all the cool air is going out of the room.
The reason the airconditioners work extra hard is because they have a temperature sensor that is used to keep the room at a certain temperature. Once that temperature is reached, the AC stops. After time the temperature raises to a certain point and then the AC starts again. This keeps the room at a somewhat constant temperature. If a door or window is left open, the temperature goes up quicker and so the AC has to work harder... I wonder if it would be possible to make the AC turn off using a motion sensor... It probably is...
What is the cost to the school for your classroom, team space, and grade level?
Do you understand how solar power works? Where would it be efficient to use solar power where it is not yet being used?
Do you understand how the ice plant works?
What ARE renewable energy sources?
sources that can be used over and over again without any effects on the resource (it replenishes)
Are all forms of alternative energy good for the planet?
Depends
Hydro-electric is another for of energy. Doesn't it convert the flowing water into energy? Isn't one of the main places at dam sight?
GEOTHERMAL POWER
Geothermal power rotates around the idea of using the expansion and rising power of steam to turn a turbine. Water is pumped into a geothermal reservoir and is heated. In a "steam" geothermal power plant the water is turned to steam and is piped to the turbines and generates electricity. In a "hot water” geothermal power plant the water in the reservoir is heated to anywhere between 300 and 700 degrees and piped to the top, where it explodes into steam and turns a turbine. Finally a "heat” geothermal power plant produces heated water from the reservoir, and although it does not have the necessary heat to explode into steam like in a "hot water" plant it is used to heat a liquid that turns into steam at lower temperatures, turning a turbine.
There is a geothermal power plant in Puna on the Big Island of Hawaii where they produce 30 MW, but for the most part this is only a viable energy solution for the whole of Hawaii, because Punahou lacks the land, location (we aren't by an active volcano), and money (for drilling) to produce geothermal energy. Like all energy sources, however, it makes for an excellent research project.
HYDROELECTRIC POWER
Typically Hydro-power is generated through the use of a dam, which slows the flow of water to a relative trickle. This creates a difference in water height between the two sides of the dam. When this occurs there is move force backing the trickle of water, which is used to push a turbine. This is typically very
efficient and produces a great deal of energy. However it has it's own limitations and drawbacks. You can not build a Dam is you do not have a large river or lake, and doing so changes the landscape by flooding one side and drying up the other (a serious problem with developed areas). It also hurts near by ecosystems by flooding and impeding their water sources, and by decreasing water quality.
Tidal power plants work in a similar manner to the dam, but instead of impeding a river or lake to produce power the dam block an entire or part of a bay. As the tide rises due to the gravitational pull of the sun and moon, a difference in water height is created. This is better by comparison because you don't have to worry about many of the flooding concerns, and is equally renewable. However it still disrupts some coastal and tide pool ecosystems. It also requires a used bay and plenty of room.
Potential for these power sources do not exist on the land owned by Punahou School (unless we use tidal in the lily pond... which is stupid) and so is an unlikely solution to our energy goals. However these forms of power plants still hold great promise for the rest of the state of Hawaii, and may be an interesting topic for children in the lower schools to learn about. One possible experiment that lower grades or people taking biology could do is an examination of how this would affect the ecosystems living in side the tidal dam. Another interesting project would be to design a tidal energy system.
There is also another kind of tidal energy that uses the energy of offshore turbines. Again, only for the benefit of the state of Hawaii. (Link)
SOLAR POWER
Photovoltaic Cells or Solar Cells basically work by taking usually 2 forms of Silicon, N-type and P-type. The N-type (the N stands for negative) silicon caries other choice impurities that have an extra electron in them and P-type is exactly the opposite. When the sun hits the N-type silicon giving of a burst of energy to the extra energy allowing the extra electron to move to the other side and create a current.
Asking student's to experiment with this is not a good thing as the temperature needed to process these materials is above 2500 degree's, and extremely dangerous. But it might be feasible to put these solar cells on all the buildings to help the school to produce it's own renewable energy instead of the HECO power plant’s.
Depending on the kind of system you have, it can cost $0.30 and $0.60 per KWH, and HECO states that for large businesses which might include Punahou that they charge about $0.1376 per KWH. This would seem to indicate to the contrary of what I have found from other articles stating that although the cost is relatively high it is still cheaper in part because of subsidies by the government and impart because most residents end up selling their power back to the system making a small profit.
There is also valuable research experience in having Chemistry students a chance to study photovoltaic. As it is one of the major pieces of evidence in support of the wave particle duality theory (the theory light is both a wave and a particle).
WIND POWER
One project students could start doing is building wind generators. Windstuffnow.com The main advantage of building the generators ourselves is the cost.
Here is a wind turbine that would generate 400 watts in 28 mph winds. Retail Price: $699.00. Here is one that was built by Windstuffnow.com that would generate 400 watts in 28 mph winds. Approximate cost: $90.00.
Note the price difference of about $609.00 in the favor of the DIY wind generator. I think that this would not only save a lot of money for the school, but would also give the students valuable team work and machine skills that we so desperately need (according to the administration).
Robotguy4's Easy Energy Saving for Your Computer:
Hold down the power button on your computer. Wait for a bit. You should not be able to read this sentence.
I find that energy effiency is the most essential part in the sustainability of Punahou. It's good that we are tyring to make renewable sources of energy such as solar power. Although I don't understand the costs of these renewable sources and the time it will take to incorporate them into school life, I believe it will be a pressing issue. We need to start conserving. For example, my family at home has an enormous electric bill. There are so many nuances that we miss that add up into wasteful, meaningless uses of energy. It's good to start somewhere. And on another note, that is not funny robotguy.
Below is a research report done by a group of Chemistry Honors students about several different alternative sources of energy. Authors: kuranaka09, kflee09, snakamoto09, schen09
ALTERNATIVE SOURCES OF ENERGY AND THE GLOBAL SOCIETY
Our research was on the different alternative sources of energy available. Not only did we want to find out about the various alternative sources of energy, but we also wanted to know what the global community has been doing with these sustainability efforts. From there, we wanted to determine how we as individuals could help our communities. First, we needed to look up the definition of an alternative source of energy. An alternative source of energy is defined as “anything other than fossil fuels which can be used for energy.”
As in many cases, there are always common misconceptions about this subject. Many people assume alternative sources of energy are equivalent to renewable sources of energy. However, alternative sources of energy include both renewable and nonrenewable sources. Thus, the alternative sources of energy not only include examples such as water power, wind power, solar power, geothermal energy, biomass energy, and hydrogen gas—all of which are renewable sources (energy that will not run out); they also include nonrenewable sources (energy that will eventually run out) such as nuclear power. In this paper, we will describe each of the sources of energy mentioned above. We will do this by writing an explanation of how each option works, their advantages, their disadvantages, how they are seen in Hawaii, and how they are used in the world.
One of the alternative energy sources we are making use of is electricity production by use of hydroelectric power stations. Water is being used to generate electricity in many ways. River power plants, tidal power stations, and wave power stations are a few of the ways in which water is being used as an alternative energy source.
Although all of these hydroelectric power stations are of different types, they all consist of a dam in which water is stored and a turbine is connected to a generator. Some turbines are driven by potential energy; others are driven by kinetic energy. The generator then transforms mechanical energy into electricity. If the water in some types of power stations has passed the turbine, it is returned to the place it came from, such as to rivers, reservoirs, oceans, etc.
The ebb and flow of the tides can be used to push air through a pipe; it can also be used to turn a turbine. However, although tides are low-cost and exist in abundance, this is not a very effective or realistic option as an alternative source of energy. To harness the power of the tides, a person would have to build a tidal barrage, like a dam. However, many estuaries also carry sewage out to sea, and if a barrage were to be built, the sewage would stick around for a longer period of time, thus creating possible environmental problems. It also affects the ecosystem because birds that wade in the water, for example, would get confused as the tide wouldn’t move properly anymore. Also, as we can only generate energy from the ebb and flow of the tides, we can only produce energy from it for around 10 hours a day, which is not exactly ideal.
While hydroelectric power is low-cost, highly efficient, and not harmful to the environment, it is not a major option as an alternative source of energy due to possible environmental concerns. Hydroelectric power plants or river power plants are around 95% effective in energy production. Many cities are already making use of hydroelectric power, but dams are not a major option as alternative energy sources because people would need a lake or large river to build a dam, and once a dam is built, it can drastically change the landscape by flooding one side and drying up the other side. This is a definite environmental concern as it harms ecosystems and decreases the quality of the water.
When the wind blows across the ocean, waves are created. Obviously, it is no problem to find waves around the globe. However, wave power plants are very rare because it is so difficult to harness this power. As most water power is, wave power is efficient, low-cost, requires no fuel, and produces no pollution. At wave power stations, the waves cause the water in the air chamber to rise and fall, which forces air in and out of a hole at the top of the chamber, which would turn a turbine and then a generator to produce energy. Another problem with wave power plants is that it is hard to create a power plant that could withstand the harsh conditions of the ocean, as waves are very strong and could damage the power plant, but still draw energy from small waves.
Many water power plants, namely river or hydroelectric power plants, are already being used around the world. In fact, hydroelectric power plants produce 19% of the world’s energy today. Tidal power stations also exist but are not as common; wave plants are even rarer! If we were able to find a solution to the possible environmental consequences, building more hydropower plants would be a highly effective, low-cost, and environmental friendly solution to our renewable energy crisis. Hydropower may not be all of the solution, but it is a definite start.
We also conducted research on wind power. This source of energy functions when blades collect the wind’s kinetic energy. As the wind flows over the shaped blades, this causes lift, which allows the blades to turn. Because the blades are also connected to a drive shaft, which is connected to an electric generator, this allows the generator to turn. The result is the production of electricity.
Wind turbines are categorized in two different groups, those with horizontal axes and those with vertical axes. Wind turbines with horizontal axes have blades like airplane propellers and are usually as high as a 20-story building. They are tall and wide so they can capture a large amount of wind. Vertical axes have blades going from top to bottom and are only usually about 100ft tall. Vertical axes wind turbines make up only about 5% of the total wind turbines used.
One turbine can produce approximately 1.5-4.0 million kilowatt hours (kWh) of electricity a year. This amount of energy can meet the needs of 150-400 homes. The United States currently generates 17 billion kWh per year, which is enough for 1.6 million households.
In the world today, many leaders are debating about the effectiveness of specific alternative sources of energy. Although our generation has finally come to realize the consequences of global warming and have knowledge of different sources of alternative energy, we have yet to decide which alternative source of energy is the best to be implemented. Because of these reasons, it makes sense to weigh out the pros and cons. Wind power does have several advantages. One of the main advantages is that wind power is a clean and renewable energy source. There is no possible way to “stop” the wind; the amount of wind will never run out. Furthermore, wind power does not produce air or water pollution, and no fuel is burned. Some of the disadvantages include the clearing of wooded areas and the possibility of birds being killed by wind turbines. According to some statistics, one bird is killed per turbine every year. Another concern has to do with aesthetics. Some people believe the use of wind power will ruin the beauty of the environment, especially when turbines are found in the countryside.
In Hawaii, wind power has been used in several areas, such as in Hawaii Lalamilo Kohala, Big Island; Kama’ao South Point, Big Island; Hawi Upolu Point, Big Island; Kaheawa Pastures Ukumehame, Maui; and Kahe Ridge Nanakuli, Oahu. In the world, wind power is also becoming a more favorable option, with ultimate wind production increasing. As of 2006, the total installed capacity reached 73,904 megawatts (MW). It is projected to reach 160,000MW by 2010.
Another alternative source of energy is solar power. There are three main ways solar power is used: solar cells, solar water heating, and solar furnaces. Solar cells, also known as photovoltaic cells, convert light directly into electricity. In solar water heating, the heat from the sun is used to heat water. This is accomplished from glass panels found on the roof of houses. Water is pumped through black pipes within the panels. The pipes are black because it allows more of the Sun’s energy to be easily absorbed. Solar water heating is a good option for sunny areas such as Australia, California, and Hawaii. Another way solar power is used is through solar furnaces, which concentrates the Sun’s energy into a small area to produce high temperatures. This is done through the use of many mirrors. Currently, there is even a newer way in which solar power may be used. While this is still in consideration, people are thinking of constructing solar towers. These towers act like a greenhouse. Hot air will rise up within the tower, powering turbines along the way. As the turbines are powered, a lot of energy can be generated.
Solar power is currently used for many functions such as running satellites, which allows us to have satellite TV, telephones, navigation systems, weather forecasting, and the internet. Solar power can also produce quite a lot of energy when in sunny climates. A 100W light bulb can run from just a square meter of solar panel. In Odellio, France, a solar furnace used there can reach temperatures up to 33,000°C! In the United States, a solar plant called the Nevada Solar One can generate enough electricity to meet the needs of 40,000 homes. Solar energy allows for heating of water in homes, heating of buildings, drying of agricultural products, and generating of electrical energy.
As it shows, solar power does have many benefits. It does not require fuel, produces no waste or pollution, can be used to generate electricity in sunny regions, is a renewable energy source, and can be used to power low-power items as well, such as battery chargers and garden lights. However, there are also some negative aspects. Because solar power requires the presence of the sun, it does not work at night. Solar energy is also more useful in areas with sunny climates. Many variables in the weather may also impact the energy produced from solar power. These variables include fog and clouds. Some aspects of solar power may also be inefficient. For example, a large area of solar panels is needed to collect a useful amount of power. Furthermore, the production of solar power stations is costly. Some speculate the cost of constructing a solar power station outweighs the amount of electricity that will be produced.
Luckily, because Hawaii is known for its warm weather, solar power is gaining more importance in our state. Hawaii currently has the highest electricity prices in the nation. Because of this, the legislature has made reforms on certain policies concerning solar energy. The state has increased credit for residential photovoltaic (PV) systems up to $5000 whereas commercial PV systems are now up to $500,000. Hawaii is considered by many to one day become a leader of the solar industry in the U.S. In fact, it currently has one of the most successful solar water heating programs in the nation. 85MW of solar energy is used in the Big Island, Maui, and Oahu.
In terms of the world, worldwide production reached 1.46 Gigawatts (GW) in 2005; this number is expected to double every three years. More countries are also considering the idea of using solar energy. In Australia, a $420 million power station is under construction; it is believed this power station will have the ability to concentrate the Sun’s energy 500 times into solar cells and provide enough electricity for 450,000 homes. A 40MW plant is also under construction in Germany. Portugal is thinking of constructing plants as well. In the mainland, California has established an initiative to create 3000MW of solar-made electricity by 2017. As more countries become increasingly interested with solar energy, the cost of solar systems will eventually decrease, allowing for more consumers to use solar power as a means to obtain energy.
Another alternative source of energy is geothermal energy. Geothermal literally means “heat from the earth.” Therefore, geothermal energy uses the earth’s natural heat to generate electricity. There are three main ways of doing this. The first is through dry steam plants, which extract steam from the ground to drive a turbine and spin a generator. Another form is through flash plants, which uses hot water from the ground with temperatures over 200°C. The water boils as it rises above the ground, producing steam. The steam is then separated from the liquid phase and put into a turbine. The last form is through binary plants, which is when hot water flows through heat exchangers, such as hardened magma. This causes the organic fluid to boil, which spins a turbine. In all these forms, the remaining fluid and steam eventually are injected back into the earth.
Geothermal energy has been around for quite a while. In 1994, 18 billion kWh of electricity were produced from geothermal power; this is actually 0.3% of the total electricity used in the United States, but it was enough to support three million homes. Clean geothermal energy usually has the capacity to supply electricity to 1.5-4.0 million homes.
Like most of the alternative sources of energy we have already mentioned, geothermal energy is considered a renewable source of energy because the heat of the earth is so great. It does not burn fuels and can be found in many environments, such as deserts, mountain forests, and crop areas. It also does little harm to the environment, releasing 1-4% less carbon dioxide and 1-3% of sulfur compounds than those emitted by coal plants. In more advanced geothermal plants, there are no emissions at all. Although its little emissions can be considered an advantage, it is also a concern for those who oppose using geothermal energy. Geothermal steam and water naturally contain hydrogen sulfide and other gases or chemicals. These can all be harmful in high concentrations. Although some plants use “scrubber” systems to clean the air from those gases by converting them into marketable products or re-injecting them into the earth, this form of maintenance can be quite costly. Geothermal reservoirs are also usually seen in wilderness areas under protection. Lastly, although geothermal energy may be considered unlimited, the supply of geothermal reservoirs may eventually become unusable, which leads to the question of whether geothermal energy is actually renewable.
Because geothermal energy can be used in areas with volcanoes and geysers, Hawaii is using geothermal energy on the Big Island near Kilauea. A company known as Puna Geothermal Ventures has built a plant which uses geothermal energy to produce electricity to some Big Islanders. The plant is currently 30MW, has zero emissions, and has 100% of fluid and gas re-injected into earth. The company is planning to increase their plants to 60MW.
In the world today, the largest dry steam field is found in the Geysers, located in San Francisco, California. In just the U.S. alone, there are over 70 plants in California, Utah, Nevada, and Hawaii. Even Kenya, which is in Africa, has two plants of its own. Geothermal power is found in over 20 countries, such as Iceland, U.S., Italy, France, New Zealand, Mexico, Nicaragua, Costa Rica, Russia, Philippines, Indonesia, China, and Japan. Canada is also considering using geothermal power in British Columbia.
Besides those alternative energy sources, one of the more popular forms is the use of biomass. Biomass is matter that is commonly thought of as “garbage,” from dead trees, branches, yard clippings, crops, wood chips, bark, and saw dust to used tires and manure. It also includes paper products that cannot be recycled into other paper products and normal household waste that is sent to the dump. Biomass can be used to create biomass energy.
There are many different processes to extract energy from different types of biomass. They produce energy that can be used for different purposes. The first process is done thermochemically. This process heats but not burns the plant matter, breaking it down into different gases, solids, and liquids. These same products can further be broken down into useful fuels like methane and alcohol. Methane can then be captured with the biomass gasifiers and be burned in a gas turbine to produce electricity. Biomass energy can also be obtained biochemically, in which the use of bacteria, yeasts, and enzymes break down carbohydrates. With fermentation, biomass liquids are changed into alcohol, a combustible fuel. Methane and carbon dioxide are also formed as the bacteria breaks down biomass. The methane can then be burned for heat and power. Finally, another process of producing energy is chemically. This is done by converting biomass oils, such as canola oil and soybean oil, into a liquid fuel. An example of the fuel produced is diesel fuel. The cooking oil from restaurants is used to make “biodiesel” for trucks. However, a more effective way to produce biodiesel is to use algae as a source of oils.
Using biomass can have many advantages. One thing biomass can do is help reduce global warming by serving as fertilizer for replanting, which helps to close the carbon dioxide cycle. This is important because many alternative energy sources do not have this capability. Biomass is an environmentally helpful alternative because it can be reduced, reused and recycled as well as renewed. Biomass also improves our air quality because pollution is reduced with the energy crop fuel having no sulfur and significantly less nitrogen than fossil fuels. It also improves our water quality because the fuel contains less mercury than coal. Another advantage to using biomass is its ability to help us reduce our dependence on oil, a non-renewable fuel source, because it can produce liquid alcohol like ethanol that can be used as gasoline. It helps create a sustainable environment.
On the other hand, there are also some controversial issues pertaining to biomass as well. Some scientists believe biomass energy is what is causing global warming. Because plants consume carbon dioxide, the action of burning them for fuel increases the amount of carbon dioxide in the atmosphere, creating climate changes.
Despite this issue, biomass has still been used in many places around the world, including Hawaii. Biomass has been a source of renewable energy in Hawaii. Although Hawaii does not have a fuel plant, the Department of Business and Economic Development and Tourism completes assessments of different alternative sources that can be further explored in Hawaii.
Today, our society is also becoming more aware of another form of alternative energy, which is hydrogen gas. Hydrogen, the simplest element on earth with one proton in each atom, is also the most plentiful gas in the universe. While it has the highest energy content of any other common fuel by weight, it contains the lowest energy content by volume. It is the lightest element and is a gas at normal temperature and pressure.
Similar to electricity, hydrogen is an energy carrier and must be produced from another substance. Hydrogen can be produced from resources like water, fossil fuels, and biomass. It is also a byproduct of other chemical processes. Hydrogen can be stored in large quantities for future use while electricity has to be used quickly.
To produce hydrogen from earth, it must be separated from other elements. We can separate hydrogen atoms from water, biomass, or natural gas molecules. The two most common methods for producing hydrogen are steam reforming and electrolysis. Steam reforming is the method used to produce 95% of the hydrogen in the United States; it is the least expensive method. The process works by separating the carbon and hydrogen from its compound methane. Electrolysis is the method used to split hydrogen from water. It is currently a very expensive process, but new technologies are being developed all the time.
Hydrogen is plentiful because it is found everywhere in the world; thus, it can be considered as a sustainable fuel source. Hydrogen is also a very clean fuel when directly combusted or with hydrocarbon fuels. For example, in fuel cells, the only emissions are heat and water.
However, the process of steam reforming, which most commonly produces hydrogen, causes emissions relating to global warming. Hydrogen energy depends largely on coal and natural gases. However, the amount of natural gases is diminishing, and coal is a major contributor to pollution. The process to produce, store, and transport hydrogen power at a reasonable cost is still being explored and may take a long time.
Globally, the world is trying to enact hydrogen into their lifestyles. For example, there are about 200 hydrogen-powered vehicles in the United States. A majority of these automobiles are buses and small cars fueled by electric motors. They use a fuel cell to convert and store hydrogen gas. Only a few of these vehicles reduce pollution by burning hydrogen directly.
In more local terms, The Gas Technology Institute heads a team to lay the groundwork for using its gasifier technology that produces hydrogen from biomass. It determines which biomass produces high yields of hydrogen gas. The Hawaii Natural Energy Institute has joined this team. It assesses the potential feedstocks for biomass, such as sugarcane, bagasse, switchgrass, and various nut shells, and also how much biomass is available from each feedstock.
Finally, one of the most controversial forms of alternative sources of energy is nuclear energy. The main purpose of nuclear energy is to release energy so work such as propulsion, heat, and electricity can be created. Nuclear energy is usually produced through the use of an isotope of uranium, known as uranium-235. Because U-235 is so concentrated, nuclear fission occurs, which allows a string of controlled, chain reactions, thus releasing huge amounts of energy. In order for nuclear fission to take place, the uranium has to first be enriched so 2-3% of the uranium ore contains uranium-235. During nuclear fission, neutrons are shot into U-235, splitting the atom into two lighter atoms. When the split occurs, two or three neutrons are also thrown out as well, resulting in the chain reaction of nuclear fission. The result is a large amount of energy in the forms of heat and gamma radiation. When the nuclear fuel is no longer needed, it is sent to a repository where it can be disposed or reprocessed.
As of 2005, 16% of the world’s electricity production is from nuclear energy. The amount of energy released by uranium is so great that one pound of highly enriched uranium is equivalent to the amount of energy released by a million gallons of gasoline. One ton of uranium can produce energy greater than the energy produced by several million tons of coal or several million barrels of oil!
Although many people view the use of nuclear energy with trepidation, it does have some advantages. Nuclear power plants can still operate even when coal and oil eventually become scarce. Nuclear plants also require less fuel, and when they are well operated, they do not release contaminants into the environment; they emit little or no carbon dioxide. Nuclear technology is also available, so people do not need to spend money developing nuclear technology first in order to proceed. The most advantage nuclear technology probably has is its ability to generate high amounts of electricity in just a single plant.
However, that is not to say the concerns we often hear should not be considered. Because uranium is limited, nuclear energy is not renewable energy; it is estimated the amount of uranium will only last for the next 30-60 years, depending on demand. The building of nuclear plants also takes a very long time. There is also always the possibility of radioactive contamination, whether it is a result from an accident or from sabotage. Radiation can harm the cells of the body and make people sick. It can last in the body for long periods of time and can even result in death. If a nuclear reactor happens to undergo a meltdown, in which nuclear fission goes out of control, a nuclear explosion could result, releasing radiation into the environment. The problem with waste disposal also arises, since nuclear waste products still emit radiation and need to be stored in cooling pools for long periods of times. According to U.S. EPA standards, those cooling pools need to be constantly supervised for at least 10,000 years! Finally, as is often seen in the news, the use of nuclear energy may tempt some countries into developing nuclear weapons. Currently, countries such as Iran and North Korea are speculated to have used nuclear energy to secretly develop nuclear weapons. If nuclear energy is available to the entire world, there is always the risk of terrorist attacks, sabotage, and radiation.
According to Hawaii’s Constitution, the construction of nuclear power plants is prohibited unless two-thirds of both houses in the legislature approves. We currently do not have any nuclear energy. However, in the world, there are 30 countries operating 435 nuclear reactors for electricity purposes. This is based on information released on January 2007 by the Nuclear Energy Institute. 30 new plants are under construction in 12 countries. The top three nuclear generating countries are the United States, with 782.0 billion kWh; France, with 430.9 billion kWh; and Japan, with 280.7 billion kWh. Particularly with all the problems arising in the Middle East and North Korea, nuclear energy still remains a controversial issue in today’s current events.
With our huge dependence on foreign oil and fossil fuels, we must look towards the future to find alternative sources of energy. Thankfully, we are provided with many different options: water power, wind power, solar energy, geothermal power, biomass energy, hydrogen gas, and nuclear power. Of all these alternative energy sources, there is yet one proven to be the “best.” Each energy source has its advantages as well as its disadvantages. Some are less efficient than others, some are more costly—some are even more dangerous. In order to choose the alternative energy source which is most appropriate for us, we must consider our own environment; in this case, our home, our ‘aina. What are the best options possible for Hawaii? As an individual, we may not be able to accomplish much when it comes to establishing full-scale implementation of alternative energy sources in our state. However, because we have the information, we should attempt to promote our knowledge to the community. It is then when our government will be able to listen to our suggestions; it is then when we can make a difference.
II. Sophomore Sustainability Projects
(Click on the teacher name to see student projects.)
(Note: Some of these projects are currently not in the right places. If a project is misplaced or missing, please either make the correction yourself, if you are very sure you know what you are doing - cut and paste: but remember to save your changes as you go) or email bschauble@punahou.edu) and I'll fix it.)
Energy
This section on energy is currently divided into three parts. In the first part are some general questions and ideas about energy use. In the second section are reports on projects produced by sophomore chemistry students at Punahou. In the third are links to other web resources with regard to energy.
I. Questions and Ideas
Identify everything that uses electricity in your classroom. Is every use efficient? Is waste occurring?
- Air-conditioning takes up a lot of electricity, and there are many cases when it is left on with no one in the room
I agree, I really is not necessary to have the air conditioning on in the room without anyone in it. But what I don't get is why people have the air conditioning on and they leave the two doors open. What is the point? Is it too cold? My friends were telling me that some of the classrooms don't have control of the air-conditioning and some do. If not, what can we do to help control the problem? One of my friends told me that the air-conditioning works extra hard because all the cool air is going out of the room.The reason the airconditioners work extra hard is because they have a temperature sensor that is used to keep the room at a certain temperature. Once that temperature is reached, the AC stops. After time the temperature raises to a certain point and then the AC starts again. This keeps the room at a somewhat constant temperature. If a door or window is left open, the temperature goes up quicker and so the AC has to work harder... I wonder if it would be possible to make the AC turn off using a motion sensor... It probably is...
What is the cost to the school for your classroom, team space, and grade level?
Do you understand how solar power works? Where would it be efficient to use solar power where it is not yet being used?
Do you understand how the ice plant works?
What ARE renewable energy sources?
- sources that can be used over and over again without any effects on the resource (it replenishes)
Are all forms of alternative energy good for the planet?- Depends
Hydro-electric is another for of energy. Doesn't it convert the flowing water into energy? Isn't one of the main places at dam sight?Renewable energy resources:
GEOTHERMAL POWER
Geothermal power rotates around the idea of using the expansion and rising power of steam to turn a turbine. Water is pumped into a geothermal reservoir and is heated. In a "steam" geothermal power plant the water is turned to steam and is piped to the turbines and generates electricity. In a "hot water” geothermal power plant the water in the reservoir is heated to anywhere between 300 and 700 degrees and piped to the top, where it explodes into steam and turns a turbine. Finally a "heat” geothermal power plant produces heated water from the reservoir, and although it does not have the necessary heat to explode into steam like in a "hot water" plant it is used to heat a liquid that turns into steam at lower temperatures, turning a turbine.
There is a geothermal power plant in Puna on the Big Island of Hawaii where they produce 30 MW, but for the most part this is only a viable energy solution for the whole of Hawaii, because Punahou lacks the land, location (we aren't by an active volcano), and money (for drilling) to produce geothermal energy. Like all energy sources, however, it makes for an excellent research project.
HYDROELECTRIC POWER
Typically Hydro-power is generated through the use of a dam, which slows the flow of water to a relative trickle. This creates a difference in water height between the two sides of the dam. When this occurs there is move force backing the trickle of water, which is used to push a turbine. This is typically very
efficient and produces a great deal of energy. However it has it's own limitations and drawbacks. You can not build a Dam is you do not have a large river or lake, and doing so changes the landscape by flooding one side and drying up the other (a serious problem with developed areas). It also hurts near by ecosystems by flooding and impeding their water sources, and by decreasing water quality.
Tidal power plants work in a similar manner to the dam, but instead of impeding a river or lake to produce power the dam block an entire or part of a bay. As the tide rises due to the gravitational pull of the sun and moon, a difference in water height is created. This is better by comparison because you don't have to worry about many of the flooding concerns, and is equally renewable. However it still disrupts some coastal and tide pool ecosystems. It also requires a used bay and plenty of room.
Potential for these power sources do not exist on the land owned by Punahou School (unless we use tidal in the lily pond... which is stupid) and so is an unlikely solution to our energy goals. However these forms of power plants still hold great promise for the rest of the state of Hawaii, and may be an interesting topic for children in the lower schools to learn about. One possible experiment that lower grades or people taking biology could do is an examination of how this would affect the ecosystems living in side the tidal dam. Another interesting project would be to design a tidal energy system.
There is also another kind of tidal energy that uses the energy of offshore turbines. Again, only for the benefit of the state of Hawaii. (Link)
SOLAR POWER
Photovoltaic Cells or Solar Cells basically work by taking usually 2 forms of Silicon, N-type and P-type. The N-type (the N stands for negative) silicon caries other choice impurities that have an extra electron in them and P-type is exactly the opposite. When the sun hits the N-type silicon giving of a burst of energy to the extra energy allowing the extra electron to move to the other side and create a current.
Asking student's to experiment with this is not a good thing as the temperature needed to process these materials is above 2500 degree's, and extremely dangerous. But it might be feasible to put these solar cells on all the buildings to help the school to produce it's own renewable energy instead of the HECO power plant’s.
Depending on the kind of system you have, it can cost $0.30 and $0.60 per KWH, and HECO states that for large businesses which might include Punahou that they charge about $0.1376 per KWH. This would seem to indicate to the contrary of what I have found from other articles stating that although the cost is relatively high it is still cheaper in part because of subsidies by the government and impart because most residents end up selling their power back to the system making a small profit.
There is also valuable research experience in having Chemistry students a chance to study photovoltaic. As it is one of the major pieces of evidence in support of the wave particle duality theory (the theory light is both a wave and a particle).
WIND POWER
One project students could start doing is building wind generators. Windstuffnow.com The main advantage of building the generators ourselves is the cost.
Here is a wind turbine that would generate 400 watts in 28 mph winds. Retail Price: $699.00.
Here is one that was built by Windstuffnow.com that would generate 400 watts in 28 mph winds. Approximate cost: $90.00.
Note the price difference of about $609.00 in the favor of the DIY wind generator. I think that this would not only save a lot of money for the school, but would also give the students valuable team work and machine skills that we so desperately need (according to the administration).
How To Save Energy With Your Computer:
Here are a few simple steps to help save energy at home and at school:
http://www.eere.energy.gov/consumer/your_home/appliances/index.cfm/mytopic=10070
Robotguy4's Easy Energy Saving for Your Computer:
Hold down the power button on your computer. Wait for a bit. You should not be able to read this sentence.
I find that energy effiency is the most essential part in the sustainability of Punahou. It's good that we are tyring to make renewable sources of energy such as solar power. Although I don't understand the costs of these renewable sources and the time it will take to incorporate them into school life, I believe it will be a pressing issue. We need to start conserving. For example, my family at home has an enormous electric bill. There are so many nuances that we miss that add up into wasteful, meaningless uses of energy. It's good to start somewhere. And on another note, that is not funny robotguy.
Below is a research report done by a group of Chemistry Honors students about several different alternative sources of energy.
Authors: kuranaka09, kflee09, snakamoto09, schen09
ALTERNATIVE SOURCES OF ENERGY AND THE GLOBAL SOCIETY
Our research was on the different alternative sources of energy available. Not only did we want to find out about the various alternative sources of energy, but we also wanted to know what the global community has been doing with these sustainability efforts. From there, we wanted to determine how we as individuals could help our communities. First, we needed to look up the definition of an alternative source of energy. An alternative source of energy is defined as “anything other than fossil fuels which can be used for energy.”
As in many cases, there are always common misconceptions about this subject. Many people assume alternative sources of energy are equivalent to renewable sources of energy. However, alternative sources of energy include both renewable and nonrenewable sources. Thus, the alternative sources of energy not only include examples such as water power, wind power, solar power, geothermal energy, biomass energy, and hydrogen gas—all of which are renewable sources (energy that will not run out); they also include nonrenewable sources (energy that will eventually run out) such as nuclear power. In this paper, we will describe each of the sources of energy mentioned above. We will do this by writing an explanation of how each option works, their advantages, their disadvantages, how they are seen in Hawaii, and how they are used in the world.
One of the alternative energy sources we are making use of is electricity production by use of hydroelectric power stations. Water is being used to generate electricity in many ways. River power plants, tidal power stations, and wave power stations are a few of the ways in which water is being used as an alternative energy source.
Although all of these hydroelectric power stations are of different types, they all consist of a dam in which water is stored and a turbine is connected to a generator. Some turbines are driven by potential energy; others are driven by kinetic energy. The generator then transforms mechanical energy into electricity. If the water in some types of power stations has passed the turbine, it is returned to the place it came from, such as to rivers, reservoirs, oceans, etc.
The ebb and flow of the tides can be used to push air through a pipe; it can also be used to turn a turbine. However, although tides are low-cost and exist in abundance, this is not a very effective or realistic option as an alternative source of energy. To harness the power of the tides, a person would have to build a tidal barrage, like a dam. However, many estuaries also carry sewage out to sea, and if a barrage were to be built, the sewage would stick around for a longer period of time, thus creating possible environmental problems. It also affects the ecosystem because birds that wade in the water, for example, would get confused as the tide wouldn’t move properly anymore. Also, as we can only generate energy from the ebb and flow of the tides, we can only produce energy from it for around 10 hours a day, which is not exactly ideal.
While hydroelectric power is low-cost, highly efficient, and not harmful to the environment, it is not a major option as an alternative source of energy due to possible environmental concerns. Hydroelectric power plants or river power plants are around 95% effective in energy production. Many cities are already making use of hydroelectric power, but dams are not a major option as alternative energy sources because people would need a lake or large river to build a dam, and once a dam is built, it can drastically change the landscape by flooding one side and drying up the other side. This is a definite environmental concern as it harms ecosystems and decreases the quality of the water.
When the wind blows across the ocean, waves are created. Obviously, it is no problem to find waves around the globe. However, wave power plants are very rare because it is so difficult to harness this power. As most water power is, wave power is efficient, low-cost, requires no fuel, and produces no pollution. At wave power stations, the waves cause the water in the air chamber to rise and fall, which forces air in and out of a hole at the top of the chamber, which would turn a turbine and then a generator to produce energy. Another problem with wave power plants is that it is hard to create a power plant that could withstand the harsh conditions of the ocean, as waves are very strong and could damage the power plant, but still draw energy from small waves.
Many water power plants, namely river or hydroelectric power plants, are already being used around the world. In fact, hydroelectric power plants produce 19% of the world’s energy today. Tidal power stations also exist but are not as common; wave plants are even rarer! If we were able to find a solution to the possible environmental consequences, building more hydropower plants would be a highly effective, low-cost, and environmental friendly solution to our renewable energy crisis. Hydropower may not be all of the solution, but it is a definite start.
We also conducted research on wind power. This source of energy functions when blades collect the wind’s kinetic energy. As the wind flows over the shaped blades, this causes lift, which allows the blades to turn. Because the blades are also connected to a drive shaft, which is connected to an electric generator, this allows the generator to turn. The result is the production of electricity.
Wind turbines are categorized in two different groups, those with horizontal axes and those with vertical axes. Wind turbines with horizontal axes have blades like airplane propellers and are usually as high as a 20-story building. They are tall and wide so they can capture a large amount of wind. Vertical axes have blades going from top to bottom and are only usually about 100ft tall. Vertical axes wind turbines make up only about 5% of the total wind turbines used.
One turbine can produce approximately 1.5-4.0 million kilowatt hours (kWh) of electricity a year. This amount of energy can meet the needs of 150-400 homes. The United States currently generates 17 billion kWh per year, which is enough for 1.6 million households.
In the world today, many leaders are debating about the effectiveness of specific alternative sources of energy. Although our generation has finally come to realize the consequences of global warming and have knowledge of different sources of alternative energy, we have yet to decide which alternative source of energy is the best to be implemented. Because of these reasons, it makes sense to weigh out the pros and cons. Wind power does have several advantages. One of the main advantages is that wind power is a clean and renewable energy source. There is no possible way to “stop” the wind; the amount of wind will never run out. Furthermore, wind power does not produce air or water pollution, and no fuel is burned. Some of the disadvantages include the clearing of wooded areas and the possibility of birds being killed by wind turbines. According to some statistics, one bird is killed per turbine every year. Another concern has to do with aesthetics. Some people believe the use of wind power will ruin the beauty of the environment, especially when turbines are found in the countryside.
In Hawaii, wind power has been used in several areas, such as in Hawaii Lalamilo Kohala, Big Island; Kama’ao South Point, Big Island; Hawi Upolu Point, Big Island; Kaheawa Pastures Ukumehame, Maui; and Kahe Ridge Nanakuli, Oahu. In the world, wind power is also becoming a more favorable option, with ultimate wind production increasing. As of 2006, the total installed capacity reached 73,904 megawatts (MW). It is projected to reach 160,000MW by 2010.
Another alternative source of energy is solar power. There are three main ways solar power is used: solar cells, solar water heating, and solar furnaces. Solar cells, also known as photovoltaic cells, convert light directly into electricity. In solar water heating, the heat from the sun is used to heat water. This is accomplished from glass panels found on the roof of houses. Water is pumped through black pipes within the panels. The pipes are black because it allows more of the Sun’s energy to be easily absorbed. Solar water heating is a good option for sunny areas such as Australia, California, and Hawaii. Another way solar power is used is through solar furnaces, which concentrates the Sun’s energy into a small area to produce high temperatures. This is done through the use of many mirrors. Currently, there is even a newer way in which solar power may be used. While this is still in consideration, people are thinking of constructing solar towers. These towers act like a greenhouse. Hot air will rise up within the tower, powering turbines along the way. As the turbines are powered, a lot of energy can be generated.
Solar power is currently used for many functions such as running satellites, which allows us to have satellite TV, telephones, navigation systems, weather forecasting, and the internet. Solar power can also produce quite a lot of energy when in sunny climates. A 100W light bulb can run from just a square meter of solar panel. In Odellio, France, a solar furnace used there can reach temperatures up to 33,000°C! In the United States, a solar plant called the Nevada Solar One can generate enough electricity to meet the needs of 40,000 homes. Solar energy allows for heating of water in homes, heating of buildings, drying of agricultural products, and generating of electrical energy.
As it shows, solar power does have many benefits. It does not require fuel, produces no waste or pollution, can be used to generate electricity in sunny regions, is a renewable energy source, and can be used to power low-power items as well, such as battery chargers and garden lights. However, there are also some negative aspects. Because solar power requires the presence of the sun, it does not work at night. Solar energy is also more useful in areas with sunny climates. Many variables in the weather may also impact the energy produced from solar power. These variables include fog and clouds. Some aspects of solar power may also be inefficient. For example, a large area of solar panels is needed to collect a useful amount of power. Furthermore, the production of solar power stations is costly. Some speculate the cost of constructing a solar power station outweighs the amount of electricity that will be produced.
Luckily, because Hawaii is known for its warm weather, solar power is gaining more importance in our state. Hawaii currently has the highest electricity prices in the nation. Because of this, the legislature has made reforms on certain policies concerning solar energy. The state has increased credit for residential photovoltaic (PV) systems up to $5000 whereas commercial PV systems are now up to $500,000. Hawaii is considered by many to one day become a leader of the solar industry in the U.S. In fact, it currently has one of the most successful solar water heating programs in the nation. 85MW of solar energy is used in the Big Island, Maui, and Oahu.
In terms of the world, worldwide production reached 1.46 Gigawatts (GW) in 2005; this number is expected to double every three years. More countries are also considering the idea of using solar energy. In Australia, a $420 million power station is under construction; it is believed this power station will have the ability to concentrate the Sun’s energy 500 times into solar cells and provide enough electricity for 450,000 homes. A 40MW plant is also under construction in Germany. Portugal is thinking of constructing plants as well. In the mainland, California has established an initiative to create 3000MW of solar-made electricity by 2017. As more countries become increasingly interested with solar energy, the cost of solar systems will eventually decrease, allowing for more consumers to use solar power as a means to obtain energy.
Another alternative source of energy is geothermal energy. Geothermal literally means “heat from the earth.” Therefore, geothermal energy uses the earth’s natural heat to generate electricity. There are three main ways of doing this. The first is through dry steam plants, which extract steam from the ground to drive a turbine and spin a generator. Another form is through flash plants, which uses hot water from the ground with temperatures over 200°C. The water boils as it rises above the ground, producing steam. The steam is then separated from the liquid phase and put into a turbine. The last form is through binary plants, which is when hot water flows through heat exchangers, such as hardened magma. This causes the organic fluid to boil, which spins a turbine. In all these forms, the remaining fluid and steam eventually are injected back into the earth.
Geothermal energy has been around for quite a while. In 1994, 18 billion kWh of electricity were produced from geothermal power; this is actually 0.3% of the total electricity used in the United States, but it was enough to support three million homes. Clean geothermal energy usually has the capacity to supply electricity to 1.5-4.0 million homes.
Like most of the alternative sources of energy we have already mentioned, geothermal energy is considered a renewable source of energy because the heat of the earth is so great. It does not burn fuels and can be found in many environments, such as deserts, mountain forests, and crop areas. It also does little harm to the environment, releasing 1-4% less carbon dioxide and 1-3% of sulfur compounds than those emitted by coal plants. In more advanced geothermal plants, there are no emissions at all. Although its little emissions can be considered an advantage, it is also a concern for those who oppose using geothermal energy. Geothermal steam and water naturally contain hydrogen sulfide and other gases or chemicals. These can all be harmful in high concentrations. Although some plants use “scrubber” systems to clean the air from those gases by converting them into marketable products or re-injecting them into the earth, this form of maintenance can be quite costly. Geothermal reservoirs are also usually seen in wilderness areas under protection. Lastly, although geothermal energy may be considered unlimited, the supply of geothermal reservoirs may eventually become unusable, which leads to the question of whether geothermal energy is actually renewable.
Because geothermal energy can be used in areas with volcanoes and geysers, Hawaii is using geothermal energy on the Big Island near Kilauea. A company known as Puna Geothermal Ventures has built a plant which uses geothermal energy to produce electricity to some Big Islanders. The plant is currently 30MW, has zero emissions, and has 100% of fluid and gas re-injected into earth. The company is planning to increase their plants to 60MW.
In the world today, the largest dry steam field is found in the Geysers, located in San Francisco, California. In just the U.S. alone, there are over 70 plants in California, Utah, Nevada, and Hawaii. Even Kenya, which is in Africa, has two plants of its own. Geothermal power is found in over 20 countries, such as Iceland, U.S., Italy, France, New Zealand, Mexico, Nicaragua, Costa Rica, Russia, Philippines, Indonesia, China, and Japan. Canada is also considering using geothermal power in British Columbia.
Besides those alternative energy sources, one of the more popular forms is the use of biomass. Biomass is matter that is commonly thought of as “garbage,” from dead trees, branches, yard clippings, crops, wood chips, bark, and saw dust to used tires and manure. It also includes paper products that cannot be recycled into other paper products and normal household waste that is sent to the dump. Biomass can be used to create biomass energy.
There are many different processes to extract energy from different types of biomass. They produce energy that can be used for different purposes. The first process is done thermochemically. This process heats but not burns the plant matter, breaking it down into different gases, solids, and liquids. These same products can further be broken down into useful fuels like methane and alcohol. Methane can then be captured with the biomass gasifiers and be burned in a gas turbine to produce electricity. Biomass energy can also be obtained biochemically, in which the use of bacteria, yeasts, and enzymes break down carbohydrates. With fermentation, biomass liquids are changed into alcohol, a combustible fuel. Methane and carbon dioxide are also formed as the bacteria breaks down biomass. The methane can then be burned for heat and power. Finally, another process of producing energy is chemically. This is done by converting biomass oils, such as canola oil and soybean oil, into a liquid fuel. An example of the fuel produced is diesel fuel. The cooking oil from restaurants is used to make “biodiesel” for trucks. However, a more effective way to produce biodiesel is to use algae as a source of oils.
Using biomass can have many advantages. One thing biomass can do is help reduce global warming by serving as fertilizer for replanting, which helps to close the carbon dioxide cycle. This is important because many alternative energy sources do not have this capability. Biomass is an environmentally helpful alternative because it can be reduced, reused and recycled as well as renewed. Biomass also improves our air quality because pollution is reduced with the energy crop fuel having no sulfur and significantly less nitrogen than fossil fuels. It also improves our water quality because the fuel contains less mercury than coal. Another advantage to using biomass is its ability to help us reduce our dependence on oil, a non-renewable fuel source, because it can produce liquid alcohol like ethanol that can be used as gasoline. It helps create a sustainable environment.
On the other hand, there are also some controversial issues pertaining to biomass as well. Some scientists believe biomass energy is what is causing global warming. Because plants consume carbon dioxide, the action of burning them for fuel increases the amount of carbon dioxide in the atmosphere, creating climate changes.
Despite this issue, biomass has still been used in many places around the world, including Hawaii. Biomass has been a source of renewable energy in Hawaii. Although Hawaii does not have a fuel plant, the Department of Business and Economic Development and Tourism completes assessments of different alternative sources that can be further explored in Hawaii.
Today, our society is also becoming more aware of another form of alternative energy, which is hydrogen gas. Hydrogen, the simplest element on earth with one proton in each atom, is also the most plentiful gas in the universe. While it has the highest energy content of any other common fuel by weight, it contains the lowest energy content by volume. It is the lightest element and is a gas at normal temperature and pressure.
Similar to electricity, hydrogen is an energy carrier and must be produced from another substance. Hydrogen can be produced from resources like water, fossil fuels, and biomass. It is also a byproduct of other chemical processes. Hydrogen can be stored in large quantities for future use while electricity has to be used quickly.
To produce hydrogen from earth, it must be separated from other elements. We can separate hydrogen atoms from water, biomass, or natural gas molecules. The two most common methods for producing hydrogen are steam reforming and electrolysis. Steam reforming is the method used to produce 95% of the hydrogen in the United States; it is the least expensive method. The process works by separating the carbon and hydrogen from its compound methane. Electrolysis is the method used to split hydrogen from water. It is currently a very expensive process, but new technologies are being developed all the time.
Hydrogen is plentiful because it is found everywhere in the world; thus, it can be considered as a sustainable fuel source. Hydrogen is also a very clean fuel when directly combusted or with hydrocarbon fuels. For example, in fuel cells, the only emissions are heat and water.
However, the process of steam reforming, which most commonly produces hydrogen, causes emissions relating to global warming. Hydrogen energy depends largely on coal and natural gases. However, the amount of natural gases is diminishing, and coal is a major contributor to pollution. The process to produce, store, and transport hydrogen power at a reasonable cost is still being explored and may take a long time.
Globally, the world is trying to enact hydrogen into their lifestyles. For example, there are about 200 hydrogen-powered vehicles in the United States. A majority of these automobiles are buses and small cars fueled by electric motors. They use a fuel cell to convert and store hydrogen gas. Only a few of these vehicles reduce pollution by burning hydrogen directly.
In more local terms, The Gas Technology Institute heads a team to lay the groundwork for using its gasifier technology that produces hydrogen from biomass. It determines which biomass produces high yields of hydrogen gas. The Hawaii Natural Energy Institute has joined this team. It assesses the potential feedstocks for biomass, such as sugarcane, bagasse, switchgrass, and various nut shells, and also how much biomass is available from each feedstock.
Finally, one of the most controversial forms of alternative sources of energy is nuclear energy. The main purpose of nuclear energy is to release energy so work such as propulsion, heat, and electricity can be created. Nuclear energy is usually produced through the use of an isotope of uranium, known as uranium-235. Because U-235 is so concentrated, nuclear fission occurs, which allows a string of controlled, chain reactions, thus releasing huge amounts of energy. In order for nuclear fission to take place, the uranium has to first be enriched so 2-3% of the uranium ore contains uranium-235. During nuclear fission, neutrons are shot into U-235, splitting the atom into two lighter atoms. When the split occurs, two or three neutrons are also thrown out as well, resulting in the chain reaction of nuclear fission. The result is a large amount of energy in the forms of heat and gamma radiation. When the nuclear fuel is no longer needed, it is sent to a repository where it can be disposed or reprocessed.
As of 2005, 16% of the world’s electricity production is from nuclear energy. The amount of energy released by uranium is so great that one pound of highly enriched uranium is equivalent to the amount of energy released by a million gallons of gasoline. One ton of uranium can produce energy greater than the energy produced by several million tons of coal or several million barrels of oil!
Although many people view the use of nuclear energy with trepidation, it does have some advantages. Nuclear power plants can still operate even when coal and oil eventually become scarce. Nuclear plants also require less fuel, and when they are well operated, they do not release contaminants into the environment; they emit little or no carbon dioxide. Nuclear technology is also available, so people do not need to spend money developing nuclear technology first in order to proceed. The most advantage nuclear technology probably has is its ability to generate high amounts of electricity in just a single plant.
However, that is not to say the concerns we often hear should not be considered. Because uranium is limited, nuclear energy is not renewable energy; it is estimated the amount of uranium will only last for the next 30-60 years, depending on demand. The building of nuclear plants also takes a very long time. There is also always the possibility of radioactive contamination, whether it is a result from an accident or from sabotage. Radiation can harm the cells of the body and make people sick. It can last in the body for long periods of time and can even result in death. If a nuclear reactor happens to undergo a meltdown, in which nuclear fission goes out of control, a nuclear explosion could result, releasing radiation into the environment. The problem with waste disposal also arises, since nuclear waste products still emit radiation and need to be stored in cooling pools for long periods of times. According to U.S. EPA standards, those cooling pools need to be constantly supervised for at least 10,000 years! Finally, as is often seen in the news, the use of nuclear energy may tempt some countries into developing nuclear weapons. Currently, countries such as Iran and North Korea are speculated to have used nuclear energy to secretly develop nuclear weapons. If nuclear energy is available to the entire world, there is always the risk of terrorist attacks, sabotage, and radiation.
According to Hawaii’s Constitution, the construction of nuclear power plants is prohibited unless two-thirds of both houses in the legislature approves. We currently do not have any nuclear energy. However, in the world, there are 30 countries operating 435 nuclear reactors for electricity purposes. This is based on information released on January 2007 by the Nuclear Energy Institute. 30 new plants are under construction in 12 countries. The top three nuclear generating countries are the United States, with 782.0 billion kWh; France, with 430.9 billion kWh; and Japan, with 280.7 billion kWh. Particularly with all the problems arising in the Middle East and North Korea, nuclear energy still remains a controversial issue in today’s current events.
With our huge dependence on foreign oil and fossil fuels, we must look towards the future to find alternative sources of energy. Thankfully, we are provided with many different options: water power, wind power, solar energy, geothermal power, biomass energy, hydrogen gas, and nuclear power. Of all these alternative energy sources, there is yet one proven to be the “best.” Each energy source has its advantages as well as its disadvantages. Some are less efficient than others, some are more costly—some are even more dangerous. In order to choose the alternative energy source which is most appropriate for us, we must consider our own environment; in this case, our home, our ‘aina. What are the best options possible for Hawaii? As an individual, we may not be able to accomplish much when it comes to establishing full-scale implementation of alternative energy sources in our state. However, because we have the information, we should attempt to promote our knowledge to the community. It is then when our government will be able to listen to our suggestions; it is then when we can make a difference.
II. Sophomore Sustainability Projects
(Click on the teacher name to see student projects.)
(Note: Some of these projects are currently not in the right places. If a project is misplaced or missing, please either make the correction yourself, if you are very sure you know what you are doing - cut and paste: but remember to save your changes as you go) or email bschauble@punahou.edu) and I'll fix it.)
Mr. Kaya's Class
Mr. Herbert's Class
Mr. Hu's Class
III. Website Sources:
http://www.heco.com/vcmcontent/FileScan/PDFConvert/giovanni.pdf
http://state.hi.us/dbedt/ert/wwg/history.html
http://www.power-technology.com/projects/hawaii/
http://www.eia.doe.gov/kids/energyfacts/sources/renewable/wind.html
http://www.solcomhouse.com/windpower.htm
http://www.telosnet.com/wind/future.html
http://www.powerscorecard.org/tech_detail.cfm?resource_id=11http://home.clara.net/darvill/altenerg/solar.htm
http://www.scienceclarified.com/Al-As/Alternative-Energy-Sources.html
http://en.wikipedia.org/wiki/Renewable_energy
http://www.forsolar.org/?q=node/4
http://www.hawaiisenergyfuture.com
http://lomaprieta.sierraclub.org/greenpower/renewabletech.htm#Geothermal
http://www.nei.org/
http://library.thinkquest.org/3471/nuclear_energy_body.html
http://home.clara.net/darvill/altenerg/images/MarineTurbines.jpg
http://earthsci.org/mineral/energy/hydro/hydroplant-animate.gif
http://img.search.com/thumb/a/a4/Water_turbine.jpg/260px-Water_turbine.jpg
http://www.navitron.org.uk/Dam.jpg
http://en.wikipedia.org/wiki/Water_power
http://www.discoverychannel.co.uk/technology/alternative_energy/water/index.shtml
http://library.thinkquest.org/26366/text/alternative/otec.html
http://www.rise.org.au/info/Tech/geo/index.html
http://www.gcse.com
http://www.flyaway.canalblog.com
http://www.worldchanging.com
http://www.ecolo.org
http://wwww.energy.iastate.edu
http://www.scienceacross.org
http://www.hawaii-county.com
http://www.mccullagh.org
http://www.liv.ac.uk
http://www.alternate-energy-sources.com
http://www.theage.com.au
http://www.csumsm.edu
http://www.art.com
http://www.energyquest.ca.gov/story/index.html#table
http://www.ucsusa.org/general/404.html
http://www.treepower.org
http://www.hnei.hawaii.edu/bio.assess.asp
http://www.eia.doe.gov/kids/energyfacts/sources/IntermediateHydrogen.html
http://www.cecarf.org/Programs/Fuels/Fuelfacts/HydrogenFacts.html__